1. Field of the Invention
Example embodiments relate to a semiconductor and a semiconductor manufacturing method. Other example embodiments relate to a polymer, a top coating layer, a top coating composition and an immersion lithography process using the same.
2. Description of the Related Art
Because semiconductor devices are becoming more highly integrated, more delicate and accurate patterning may be necessary or desired. The width of a photoresist pattern available in an exposure process may be determined according to Rayleigh's equation, R=(k1)(λ/NA) wherein R represents resolution, k1 represents a process constant, λ represents a wavelength of a light source and NA (numerical aperture) represents an effective aperture of a lens. To reduce the resolution, the process constant (k1) may be smaller, the wavelength of a light source (λ) may be shorter and/or the effective aperture of a lens may be increased.
To generate a light source having a wavelength shorter than the wavelength of KrF (248 mm) or ArF (193 mm) as used in the related art, an exposure process using an extreme ultraviolet (EUV) as a light source having a wavelength of 13.4 nm may be necessary. The exposure process using the EUV as the light source may require a vacuum condition and a reflective photomask, which may be different from the vacuum condition and the reflective photomask used in the related art processes. The exposure equipment necessary to use the EUV as the light source may be costly, making use of the exposure equipment for the exposure process an undesirable option.
The effective aperture of a lens (NA) may be proportional to n sin θ wherein n represents a refractive index of a medium between a lens and a photoresist. Because n represents the refractive index of the medium between the lens and photoresist, resolution increases as the refractive index of the medium increases.
In an immersion lithography process exploiting the relationship between the resolution and the refractive index, an exposure process may be performed to increase resolution through a medium (having a refractive index higher than the refractive index of air) and an ArF light source used in the related art. Water, which has a refractive index of 1.4, has a refractive index higher than air, which has a refractive index of 1. As such, water may be used as the medium.
If the exposure process is performed using water as the medium, then a photosensitive polymer, a photoacid generator and a solvent may be dissolved into the water. If the exposure process is performed using water as the medium, then bubbles may form on a boundary between the water and a photoresist layer. Because of the solubility of the solvent in the water and/or the formation of the bubbles, it may be difficult to form a photoresist pattern with improved accuracy.
Because of the solubility of the solvent in the water and/or the formation of the bubbles, a top coating layer may be necessary. The top coating layer may protect a photoresist layer from the water. The top coating layer may have a hydrophobicity (e.g., lacking affinity for water) and a light transmitting property. The top coating layer may be more easily removed in a developer. The use of fluoropolymer materials in a top coating layer has been acknowledged in the related art. The fluoropolymer materials may be costly and more difficult to manufacture. As such, the fluoropolymer materials may not be easily commercialized.